DVD (digital versatile disk) video format is one of playback only standards of digital versatile disks (DVDs). In the DVD video format, content data such as video and audio is multiplexed with data of a variety of sub-pictures including caption, and is recorded in a program stream on a disk. Navigation data is also recorded on the disk to reproduce interactively the stream.
In interactive reproduction, data is reproduced at a desired position or in a desired order. In the interactive reproduction, users can use a variety of functions of DVD. The available functions include a multi-angle function in which videos captured at various angles are reproduced, a multi-language function in which data is reproduced in a desired language selected from a plurality of languages, a parental control function in which a particular scene, such as a scene of violence, is prevented from being reproduced.
A program stream can be produced by multiplexing a plurality of audio streams and a plurality of caption data streams. If data of different languages is thus recorded for one video content, such as a movie, on a single disk, a user can select voice and caption of a desirable language at the beginning of or during video reproduction.
Patent Document 1 discloses a system that allows a user to easily download a content as a video work, including sound effects, moving image, and still image. Patent Document 2 discloses a technique that allows a portion of entire music data to be replaced with another data.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2003-140662
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2002-311967